In fluid systems having a plurality of work elements, for example in an excavator having a plurality of pumps serving respective work elements through separate circuits, it is desirable to provide controls for providing fluid to the work elements in a preselected order, controllably combining fluid in a preselected order between the circuits, and controllably increasing the fluid available to preselected work elements during preselected modes of operation of the excavator.
By providing the controls of this invention, the excavator has increased versatility and efficiency and the waste of materials, power, and time is reduced.
According to the present invention, a fluid system has at least one pressurized fluid source serving a respective first, second, and third fluid circuit. The first circuit has a first work element and the second and third circuits each have a plurality of work elements connected in interruptible series. Means are connected to each respective work element for selectively, controllably passing fluid to and from the work elements. A selecting means has a selecting element that is movable between first and second positions. At the first position of the selecting element, excess fluid delivered by the first pump to the first circuit is diverted to the second and third circuits. At the second position of the selecting element, excess fluid delivered to the first circuit is diverted to preselected work elements.